The broadcasting of services to mobile receivers, such as, for example, cell phones or personal digital assistants, notably comprises a step for generating the contribution signal and a step for receiving and forwarding services by regional terrestrial transmitters. The contribution signal is, for example, routed to the various regions via a satellite contribution link. However, the available bandwidth on a satellite is particularly limited and therefore costly.
The broadcasting of services to mobile receivers can use techniques for broadcasting data in successive bursts, as proposed, for example, by the DVB-H standard. This technique makes it possible to make substantial energy savings on the receivers. The current means make it possible to broadcast services to mobile receivers while optimizing the bandwidth used on the contribution link. However, such systems do not manage a contribution link delivering global broadcasting services and regional services to several terrestrial networks distributed over several geographic areas and with the data broadcast in bursts. To broadcast global and regional services in bursts to several regions, it is necessary to broadcast, for each region, the global services and specific regional services. Also, the transmission, for each region, of regional and global broadcast data leads to a redundancy of the global broadcasting information and an under-optimized use of the satellite resources.
The broadcasting of global and regional services in data bursts to several regions comes up against the complexity of reconstructing the original stream after the step for receiving the contribution signal.
Furthermore, the broadcasting of services in bursts is normally done using a single frequency network infrastructure. The terrestrial transmitters that broadcast the regional services must be synchronized. For this, the receivers receive synchronization information originating from the contribution link in the form of synchronization frames or “mega-frame initialization packets” (MIP). The broadcasting of global and regional services in bursts to several regions must therefore restore the MIP frames on reception without altering their accuracy. Each MIP frame, inserted regularly into the stream, delivers a time reference between the stream and a reference clock. Thus, the deviations and jitter between the transfer times from the satellite to the various regions can be eliminated. Equipment suitable for inserting MIP frames can correctly insert the MIP frames into a stream whose bit rate is known and constant between the moment when the stream is sent and the moment when the stream is received. However, it is not possible to use them in a contribution context. In practice, the bit rate of the contribution signal can differ from the bit rate of the signal broadcast in a given geographic region, since certain services may not concern certain regions. Since the bit rate differs between the signal transmitted over the contribution link and the signal received by the transmitters, the values included in the MIP frames inserted by equipment suitable for inserting MIP frames are incorrect.